Loved the premise of this
story: Dean as a patient in a psychiatric hospital. It seems almost AU at first; Dean's clearly a few cans short of a six-pack here. There are subtle clues about what's really going on though, and once I realised that, I just had to go back and reread it to appreciate all the hints. The supernatural forces here are actually just a backdrop for the story; the real heart of this piece is Dean's situation.
Oh, and have fun figuring out the main secret. Even if you don't in the first part, it becomes pretty clear in part 2.